1. Field of the Invention
The present invention pertains generally to trim strips for application to edges, flanges, joints and the like such as commonly found around the door and window openings of automotive vehicles. More particularly, it pertains to such trim strips incorporating a stamped metal carrier or stiffener and which are free of the surface inconsistencies, or peak and valleys, heretofore characteristic of such strips, and to a method for manufacturing such trim strips.
2. Description of the Prior Art
Trim elements or strips of the aforedescribed type which are commonly employed, among other places, around the window and door openings of automotive vehicles, include a portion of channel-shaped cross-section and generally comprise a core member of stiffener as of sheet metal embedded in a surrounding body of a rubber-like material such as a synthetic resin. Such trim strips are generally formed as a continuous extrusion and are disclosed, for example, in U.S. Pat. Nos. 4,232,081 to Pullan and 4,432,166 to Weimar. The function of the core member or stiffener is to afford shape retention to the composite structure. The structure must nevertheless be sufficiently flexible and deformable as to be readily adaptable to the configuration of the support member to which it is to be applied. Thus, the embedded stiffener must not prevent the trip strip from being readily bent and twisted to a desired configuration, nor buckle upon such bending and twisting.
To that end, the stiffener may comprise a network of perforated, slotted, woven or expanded metal or similar material having spaces and interconnecting portions. When thus formed into a channel shape and embedded in the surrounding body of rubber-like material or synthetic resin, the core member or stiffener maintains the desired channel shape of the trim strip, and yet the composite structure is capable of being readily bent and shaped about its longitudinal axis to the desired configuration. Channel-shaped trim members having stamped metal stiffeners are disclosed, for example, in U.S. Pat. Nos. 4,339,860 to Hayashi and 4,355,448 to Ezaki. While they exhibit the aforementioned advantages over similar trim strips having a solid metal stiffener, it has been found that when the stamped metal stiffener is extruded into the rubber-like material or synthetic resin, the pattern of the stiffener carries over and is visible upon the surface of the extruded section. In other words, there is created on the surface a system of inconsistencies appearing as peaks and valleys and having an undesirable appearance commonly referred to in the art as a "hungry horse" pattern.